kernel/linux.git/drivers/net/vrf.c, branch v5.10.78

vrf: Revert "Reset skb conntrack connection..."

2021-11-06T13:10:09+00:00

commit 55161e67d44fdd23900be166a81e996abd6e3be9 upstream. This reverts commit 09e856d54bda5f288ef8437a90ab2b9b3eab83d1. When an interface is enslaved in a VRF, prerouting conntrack hook is called twice: once in the context of the original input interface, and once in the context of the VRF interface. If no special precausions are taken, this leads to creation of two conntrack entries instead of one, and breaks SNAT. Commit above was intended to avoid creation of extra conntrack entries when input interface is enslaved in a VRF. It did so by resetting conntrack related data associated with the skb when it enters VRF context. However it breaks netfilter operation. Imagine a use case when conntrack zone must be assigned based on the original input interface, rather than VRF interface (that would make original interfaces indistinguishable). One could create netfilter rules similar to these: chain rawprerouting { type filter hook prerouting priority raw; iif realiface1 ct zone set 1 return iif realiface2 ct zone set 2 return } This works before the mentioned commit, but not after: zone assignment is "forgotten", and any subsequent NAT or filtering that is dependent on the conntrack zone does not work. Here is a reproducer script that demonstrates the difference in behaviour. ========== #!/bin/sh # This script demonstrates unexpected change of nftables behaviour # caused by commit 09e856d54bda5f28 ""vrf: Reset skb conntrack # connection on VRF rcv" # https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=09e856d54bda5f288ef8437a90ab2b9b3eab83d1 # # Before the commit, it was possible to assign conntrack zone to a # packet (or mark it for `notracking`) in the prerouting chanin, raw # priority, based on the `iif` (interface from which the packet # arrived). # After the change, # if the interface is enslaved in a VRF, such # assignment is lost. Instead, assignment based on the `iif` matching # the VRF master interface is honored. Thus it is impossible to # distinguish packets based on the original interface. # # This script demonstrates this change of behaviour: conntrack zone 1 # or 2 is assigned depending on the match with the original interface # or the vrf master interface. It can be observed that conntrack entry # appears in different zone in the kernel versions before and after # the commit. IPIN=172.30.30.1 IPOUT=172.30.30.2 PFXL=30 ip li sh vein >/dev/null 2>&1 && ip li del vein ip li sh tvrf >/dev/null 2>&1 && ip li del tvrf nft list table testct >/dev/null 2>&1 && nft delete table testct ip li add vein type veth peer veout ip li add tvrf type vrf table 9876 ip li set veout master tvrf ip li set vein up ip li set veout up ip li set tvrf up /sbin/sysctl -w net.ipv4.conf.veout.accept_local=1 /sbin/sysctl -w net.ipv4.conf.veout.rp_filter=0 ip addr add $IPIN/$PFXL dev vein ip addr add $IPOUT/$PFXL dev veout nft -f - <<__END__ table testct { chain rawpre { type filter hook prerouting priority raw; iif { veout, tvrf } meta nftrace set 1 iif veout ct zone set 1 return iif tvrf ct zone set 2 return notrack } chain rawout { type filter hook output priority raw; notrack } } __END__ uname -rv conntrack -F ping -W 1 -c 1 -I vein $IPOUT conntrack -L Signed-off-by: Eugene Crosser Acked-by: David Ahern Signed-off-by: David S. Miller Cc: Florian Westphal Signed-off-by: Greg Kroah-Hartman

vrf: Reset skb conntrack connection on VRF rcv

2021-08-26T12:35:47+00:00

[ Upstream commit 09e856d54bda5f288ef8437a90ab2b9b3eab83d1 ] To fix the "reverse-NAT" for replies. When a packet is sent over a VRF, the POST_ROUTING hooks are called twice: Once from the VRF interface, and once from the "actual" interface the packet will be sent from: 1) First SNAT: l3mdev_l3_out() -> vrf_l3_out() -> .. -> vrf_output_direct() This causes the POST_ROUTING hooks to run. 2) Second SNAT: 'ip_output()' calls POST_ROUTING hooks again. Similarly for replies, first ip_rcv() calls PRE_ROUTING hooks, and second vrf_l3_rcv() calls them again. As an example, consider the following SNAT rule: > iptables -t nat -A POSTROUTING -p udp -m udp --dport 53 -j SNAT --to-source 2.2.2.2 -o vrf_1 In this case sending over a VRF will create 2 conntrack entries. The first is from the VRF interface, which performs the IP SNAT. The second will run the SNAT, but since the "expected reply" will remain the same, conntrack randomizes the source port of the packet: e..g With a socket bound to 1.1.1.1:10000, sending to 3.3.3.3:53, the conntrack rules are: udp 17 29 src=2.2.2.2 dst=3.3.3.3 sport=10000 dport=53 packets=1 bytes=68 [UNREPLIED] src=3.3.3.3 dst=2.2.2.2 sport=53 dport=61033 packets=0 bytes=0 mark=0 use=1 udp 17 29 src=1.1.1.1 dst=3.3.3.3 sport=10000 dport=53 packets=1 bytes=68 [UNREPLIED] src=3.3.3.3 dst=2.2.2.2 sport=53 dport=10000 packets=0 bytes=0 mark=0 use=1 i.e. First SNAT IP from 1.1.1.1 --> 2.2.2.2, and second the src port is SNAT-ed from 10000 --> 61033. But when a reply is sent (3.3.3.3:53 -> 2.2.2.2:61033) only the later conntrack entry is matched: udp 17 29 src=2.2.2.2 dst=3.3.3.3 sport=10000 dport=53 packets=1 bytes=68 src=3.3.3.3 dst=2.2.2.2 sport=53 dport=61033 packets=1 bytes=49 mark=0 use=1 udp 17 28 src=1.1.1.1 dst=3.3.3.3 sport=10000 dport=53 packets=1 bytes=68 [UNREPLIED] src=3.3.3.3 dst=2.2.2.2 sport=53 dport=10000 packets=0 bytes=0 mark=0 use=1 And a "port 61033 unreachable" ICMP packet is sent back. The issue is that when PRE_ROUTING hooks are called from vrf_l3_rcv(), the skb already has a conntrack flow attached to it, which means nf_conntrack_in() will not resolve the flow again. This means only the dest port is "reverse-NATed" (61033 -> 10000) but the dest IP remains 2.2.2.2, and since the socket is bound to 1.1.1.1 it's not received. This can be verified by logging the 4-tuple of the packet in '__udp4_lib_rcv()'. The fix is then to reset the flow when skb is received on a VRF, to let conntrack resolve the flow again (which now will hit the earlier flow). To reproduce: (Without the fix "Got pkt_to_nat_port" will not be printed by running 'bash ./repro'): $ cat run_in_A1.py import logging logging.getLogger("scapy.runtime").setLevel(logging.ERROR) from scapy.all import * import argparse def get_packet_to_send(udp_dst_port, msg_name): return Ether(src='11:22:33:44:55:66', dst=iface_mac)/ \ IP(src='3.3.3.3', dst='2.2.2.2')/ \ UDP(sport=53, dport=udp_dst_port)/ \ Raw(f'{msg_name}\x0012345678901234567890') parser = argparse.ArgumentParser() parser.add_argument('-iface_mac', dest="iface_mac", type=str, required=True, help="From run_in_A3.py") parser.add_argument('-socket_port', dest="socket_port", type=str, required=True, help="From run_in_A3.py") parser.add_argument('-v1_mac', dest="v1_mac", type=str, required=True, help="From script") args, _ = parser.parse_known_args() iface_mac = args.iface_mac socket_port = int(args.socket_port) v1_mac = args.v1_mac print(f'Source port before NAT: {socket_port}') while True: pkts = sniff(iface='_v0', store=True, count=1, timeout=10) if 0 == len(pkts): print('Something failed, rerun the script :(', flush=True) break pkt = pkts[0] if not pkt.haslayer('UDP'): continue pkt_sport = pkt.getlayer('UDP').sport print(f'Source port after NAT: {pkt_sport}', flush=True) pkt_to_send = get_packet_to_send(pkt_sport, 'pkt_to_nat_port') sendp(pkt_to_send, '_v0', verbose=False) # Will not be received pkt_to_send = get_packet_to_send(socket_port, 'pkt_to_socket_port') sendp(pkt_to_send, '_v0', verbose=False) break $ cat run_in_A2.py import socket import netifaces print(f"{netifaces.ifaddresses('e00000')[netifaces.AF_LINK][0]['addr']}", flush=True) s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM) s.setsockopt(socket.SOL_SOCKET, socket.SO_BINDTODEVICE, str('vrf_1' + '\0').encode('utf-8')) s.connect(('3.3.3.3', 53)) print(f'{s. getsockname()[1]}', flush=True) s.settimeout(5) while True: try: # Periodically send in order to keep the conntrack entry alive. s.send(b'a'*40) resp = s.recvfrom(1024) msg_name = resp[0].decode('utf-8').split('\0')[0] print(f"Got {msg_name}", flush=True) except Exception as e: pass $ cat repro.sh ip netns del A1 2> /dev/null ip netns del A2 2> /dev/null ip netns add A1 ip netns add A2 ip -n A1 link add _v0 type veth peer name _v1 netns A2 ip -n A1 link set _v0 up ip -n A2 link add e00000 type bond ip -n A2 link add lo0 type dummy ip -n A2 link add vrf_1 type vrf table 10001 ip -n A2 link set vrf_1 up ip -n A2 link set e00000 master vrf_1 ip -n A2 addr add 1.1.1.1/24 dev e00000 ip -n A2 link set e00000 up ip -n A2 link set _v1 master e00000 ip -n A2 link set _v1 up ip -n A2 link set lo0 up ip -n A2 addr add 2.2.2.2/32 dev lo0 ip -n A2 neigh add 1.1.1.10 lladdr 77:77:77:77:77:77 dev e00000 ip -n A2 route add 3.3.3.3/32 via 1.1.1.10 dev e00000 table 10001 ip netns exec A2 iptables -t nat -A POSTROUTING -p udp -m udp --dport 53 -j \ SNAT --to-source 2.2.2.2 -o vrf_1 sleep 5 ip netns exec A2 python3 run_in_A2.py > x & XPID=$! sleep 5 IFACE_MAC=`sed -n 1p x` SOCKET_PORT=`sed -n 2p x` V1_MAC=`ip -n A2 link show _v1 | sed -n 2p | awk '{print $2'}` ip netns exec A1 python3 run_in_A1.py -iface_mac ${IFACE_MAC} -socket_port \ ${SOCKET_PORT} -v1_mac ${SOCKET_PORT} sleep 5 kill -9 $XPID wait $XPID 2> /dev/null ip netns del A1 ip netns del A2 tail x -n 2 rm x set +x Fixes: 73e20b761acf ("net: vrf: Add support for PREROUTING rules on vrf device") Signed-off-by: Lahav Schlesinger Reviewed-by: David Ahern Link: https://lore.kernel.org/r/20210815120002.2787653-1-lschlesinger@drivenets.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin

vrf: do not push non-ND strict packets with a source LLA through packet taps again

2021-07-14T14:56:24+00:00

[ Upstream commit 603113c514e95c3350598bc3cccbd03af7ea4ab2 ] Non-ND strict packets with a source LLA go through the packet taps again, while non-ND strict packets with other source addresses do not, and we can see a clone of those packets on the vrf interface (we should not). This is due to a series of changes: Commit 6f12fa775530[1] made non-ND strict packets not being pushed again in the packet taps. This changed with commit 205704c618af[2] for those packets having a source LLA, as they need a lookup with the orig_iif. The issue now is those packets do not skip the 'vrf_ip6_rcv' function to the end (as the ones without a source LLA) and go through the check to call packet taps again. This check was changed by commit 6f12fa775530[1] and do not exclude non-strict packets anymore. Packets matching 'need_strict && !is_ndisc && is_ll_src' are now being sent through the packet taps again. This can be seen by dumping packets on the vrf interface. Fix this by having the same code path for all non-ND strict packets and selectively lookup with the orig_iif for those with a source LLA. This has the effect to revert to the pre-205704c618af[2] condition, which should also be easier to maintain. [1] 6f12fa775530 ("vrf: mark skb for multicast or link-local as enslaved to VRF") [2] 205704c618af ("vrf: packets with lladdr src needs dst at input with orig_iif when needs strict") Fixes: 205704c618af ("vrf: packets with lladdr src needs dst at input with orig_iif when needs strict") Cc: Stephen Suryaputra Reported-by: Paolo Abeni Signed-off-by: Antoine Tenart Reviewed-by: David Ahern Signed-off-by: David S. Miller Signed-off-by: Sasha Levin

vrf: fix maximum MTU

2021-06-23T12:42:41+00:00

[ Upstream commit 9bb392f62447d73cc7dd7562413a2cd9104c82f8 ] My initial goal was to fix the default MTU, which is set to 65536, ie above the maximum defined in the driver: 65535 (ETH_MAX_MTU). In fact, it's seems more consistent, wrt min_mtu, to set the max_mtu to IP6_MAX_MTU (65535 + sizeof(struct ipv6hdr)) and use it by default. Let's also, for consistency, set the mtu in vrf_setup(). This function calls ether_setup(), which set the mtu to 1500. Thus, the whole mtu config is done in the same function. Before the patch: $ ip link add blue type vrf table 1234 $ ip link list blue 9: blue: mtu 65536 qdisc noop state DOWN mode DEFAULT group default qlen 1000 link/ether fa:f5:27:70:24:2a brd ff:ff:ff:ff:ff:ff $ ip link set dev blue mtu 65535 $ ip link set dev blue mtu 65536 Error: mtu greater than device maximum. Fixes: 5055376a3b44 ("net: vrf: Fix ping failed when vrf mtu is set to 0") CC: Miaohe Lin Signed-off-by: Nicolas Dichtel Reviewed-by: David Ahern Signed-off-by: David S. Miller Signed-off-by: Sasha Levin

vrf: packets with lladdr src needs dst at input with orig_iif when needs strict

2020-12-05T21:46:07+00:00

Depending on the order of the routes to fe80::/64 are installed on the VRF table, the NS for the source link-local address of the originator might be sent to the wrong interface. This patch ensures that packets with link-local addr source is doing a lookup with the orig_iif when the destination addr indicates that it is strict. Add the reproducer as a use case in self test script fcnal-test.sh. Fixes: b4869aa2f881 ("net: vrf: ipv6 support for local traffic to local addresses") Signed-off-by: Stephen Suryaputra Reviewed-by: David Ahern Link: https://lore.kernel.org/r/20201204030604.18828-1-ssuryaextr@gmail.com Signed-off-by: Jakub Kicinski

vrf: Fix fast path output packet handling with async Netfilter rules

2020-11-12T15:47:06+00:00

VRF devices use an optimized direct path on output if a default qdisc is involved, calling Netfilter hooks directly. This path, however, does not consider Netfilter rules completing asynchronously, such as with NFQUEUE. The Netfilter okfn() is called for asynchronously accepted packets, but the VRF never passes that packet down the stack to send it out over the slave device. Using the slower redirect path for this seems not feasible, as we do not know beforehand if a Netfilter hook has asynchronously completing rules. Fix the use of asynchronously completing Netfilter rules in OUTPUT and POSTROUTING by using a special completion function that additionally calls dst_output() to pass the packet down the stack. Also, slightly adjust the use of nf_reset_ct() so that is called in the asynchronous case, too. Fixes: dcdd43c41e60 ("net: vrf: performance improvements for IPv4") Fixes: a9ec54d1b0cd ("net: vrf: performance improvements for IPv6") Signed-off-by: Martin Willi Link: https://lore.kernel.org/r/20201106073030.3974927-1-martin@strongswan.org Signed-off-by: Jakub Kicinski

vrf: Handle CONFIG_SYSCTL not set

2020-07-24T00:51:04+00:00

Randy reported compile failure when CONFIG_SYSCTL is not set/enabled: ERROR: modpost: "sysctl_vals" [drivers/net/vrf.ko] undefined! Fix by splitting out the sysctl init and cleanup into helpers that can be set to do nothing when CONFIG_SYSCTL is disabled. In addition, move vrf_strict_mode and vrf_strict_mode_change to above vrf_shared_table_handler (code move only) and wrap all of it in the ifdef CONFIG_SYSCTL. Update the strict mode tests to check for the existence of the /proc/sys entry. Fixes: 33306f1aaf82 ("vrf: add sysctl parameter for strict mode") Cc: Andrea Mayer Reported-by: Randy Dunlap Signed-off-by: David Ahern Acked-by: Randy Dunlap # build-tested Signed-off-by: David S. Miller

vrf: add l3mdev registration for table to VRF device lookup

2020-06-21T00:22:23+00:00

During the initialization phase of the VRF module, the callback for table to VRF device lookup is registered in l3mdev. Signed-off-by: Andrea Mayer Signed-off-by: David S. Miller

vrf: add sysctl parameter for strict mode

2020-06-21T00:22:22+00:00

Add net.vrf.strict_mode sysctl parameter. When net.vrf.strict_mode=0 (default) it is possible to associate multiple VRF devices to the same table. Conversely, when net.vrf.strict_mode=1 a table can be associated to a single VRF device. When switching from net.vrf.strict_mode=0 to net.vrf.strict_mode=1, a check is performed to verify that all tables have at most one VRF associated, otherwise the switch is not allowed. The net.vrf.strict_mode parameter is per network namespace. Signed-off-by: Andrea Mayer Signed-off-by: David S. Miller

vrf: track associations between VRF devices and tables

2020-06-21T00:22:22+00:00

Add the data structures and the processing logic to keep track of the associations between VRF devices and routing tables. When a VRF is instantiated, it needs to refer to a given routing table. For each table, we explicitly keep track of the existing VRFs that refer to the table. Signed-off-by: Andrea Mayer Signed-off-by: David S. Miller